CLIAMS:1. A composition for making compressed stabilized earth blocks, wherein the composition comprises:
red soil;
Terrazyme;
cement; and
lime.
2. The composition of claim 1 further comprising sand.
3. The composition of claim 1 wherein the Terrazyme is present in a concentration ranging from about 0.025 ml to 0.075ml, cement is present in a range of about weight percentage of 2% to 6% and lime is present in a range of about 0-4% relative to a total weight of the composition for compressed stabilized earth blocks.
4. The composition of claim 1 wherein the red soil is at least one of silt, clay or combinations thereof.
5. A method for making compressed stabilized earth blocks, wherein the method comprises:
mixing red soil, , cement, and lime to provide a composition for compressed stabilized earth blocks;
mixing the composition for compressed stabilized earth blocks with water to provide a wet composition for compressed stabilized earth blocks; and
moulding the wet composition for compressed stabilized earth blocks to provide the compressed stabilized earth blocks.
6. The method of claim 5 wherein the composition for compressed stabilized earth blocks further comprises sand.
7. The method of claim 5 wherein the red soil is at least one of silt, clay or combinations thereof.
8. A compressed stabilized earth block having a composition comprising red soil; Terrazyme; cement; and lime.
,TagSPECI:COMPOSITIONS COMPRISING TERRAZYME FOR COMPRESSED STABILIZED EARTH BLOCKS (CSEBs), METHODS THEREFOR, AND CSEBs THEREFROM
FIELD OF THE INVENTION AND USE OF INVENTION
[0001] The invention relates generally to compressed stabilized earth block and more specifically to a durable compressed stabilized earth block made using Terrazyme as environment friendly construction and building materials.
PRIOR ART AND PROBLEM TO BE SOLVED
[0002] Soil stabilization is an important stage in improving the engineering properties of the soil. Stabilization is a process of mixing admixtures with soil to improve its volume stability, strength, permeability and durability. Stabilization is considered to be an important step in the manufacture of CSEBs, and is aimed at improving the performance of a soil as a construction material.
[0003] This is typically achieved by addition of popular stabilizing agents like cement or lime in CSEBs. Amongst the variety of conventional soil stabilizers used, cement has been the most popular stabilizer in the manufacture of CSEBs. Attempts have been made by various researchers in the past to document the role of cement as a stabilizer in CSEBs. Lime has been used in stabilizing clayey soils, and has been found to impart long-term strength gain as reported in the literature. Attempts to independently utilize lime instead of cement in the preparation of CSEBs and compare their properties with those prepared with cement has been reported in the literature. Very recently, attempt to utilize lime in combination with cement as a stabilizer to achieve desirable properties of CSEBs have been reported in the literature.
[0004] It has been observed that blocks prepared with optimum quantity of lime along with cement has led to continuous buildup of strength even beyond 2 years, whereas blocks prepared with cement alone and lesser quantity of lime than optimum quantity have not gained much strength after 6 months from the time of preparation of the blocks. It can be inferred from their research findings that the utilization of stabilizers in combination in preparation of CSEBs would have beneficial effect in imparting strength and betterment of performance of CSEBs.
[0005] There is a need to further explore alternate stabilizers and its compositions for providing improved CSEBs.
OBJECTS OF THE INVENTION
[0006] There still remains a dire need in the art to improve the existing materials used for construction which retain the properties of the original materials but address the environmental concerns through sustainable production methods.
[0007] The principal object of the invention is to use Terrazyme as a stabilizing agent in preparation of compressed stabilized earth blocks. As mentioned herein prior art compressed stabilized earth blocks are stabilized using cement mostly. The use of other alternative stabilizer (non-traditional), specifically Terrazyme in combination with cement, or with cement and lime is a novel approach. Further, since Terrazyme is an eco-friendly and naturally degradable stabilizer the compositions using Terrazyme allow manufacturing of compressed stabilized earth blocks at a reduced cost due to reduction in the requirement of conventional stabilizer.
[0008] The composition of the invention comprises red soil; Terrazyme; cement; and lime.
SUMMARY OF THE INVENTION
[0009] In one aspect, the invention provides a workable dosages of Terrazyme for making compressed stabilized earth blocks. The composition of the invention comprises red soil;Terrazyme ; cement; and lime.
[0010] In another aspect, the invention provides a method for making compressed stabilized earth blocks using Terrazyme. The method comprises mixing red soil, Terrazyme cement and lime to provide the composition of the invention. The method then includes mixing composition of the invention with water to provide a wet composition for compressed stabilized earth blocks. The method then involves moulding the wet composition for compressed stabilized earth blocks to provide the compressed stabilized earth blocks.

DETAILED DESCRIPTION
[0011] The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.
[0012] As used in this specification and the appended claims, the singular forms "a", "an", and "the" encompass embodiments having plural referents, unless the content clearly dictates otherwise.
[0013] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.
[0014] As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.
[0015] As used herein, the term "Compressed Earth Block," often referred to simply as CEB, means a type of manufactured construction material formed in a mechanical press that forms an appropriate mix of dirt, non-expansive clay, and an aggregate into a compressed block. Compressed Stabilized Earth Block is used herein interchangeably with CEB. Compressed Stabilized Earth Block is sometimes abbreviated as CSEB.
[0016] Use of bio- enzyme is being currently used for stabilizing sub-grade material in road construction. This technology of enzymatic stabilization was initially used in improving the soil conditions for horticultural purposes. With its revolution in soil stabilization, sevearal bio enzymes have been developed. Terrazyme is one such type of bio-enzyme, which has been extensively used in developing countries in stabilizing subgrade soil for road construction. Being low in cost, easy to transport, and relatively having wide applicability as compared with traditional stabilizers, make terrazyme an economical stabilizing agent.
[0017] The invention provides a new composition of CSEBs that includes Terrazyme in small quantity along with an optimum combination of lime and cement for improved quality of CSEBs along with environment and economic benefits.
[0018] As noted herein, in one aspect the invention provides a composition for making compressed stabilized earth blocks. The composition comprises red soil. As used herein, red soil refers to one of the mineral soils which contain no calcareous material anywhere within the soil, have less than 10% weatherable minerals in the extreme top layer of soil, and have less than 35% base saturation throughout the soil. They may be referred to as Ultisols, Acrisols, Lixisols, or Nitosols, depending on the source of the soil or the classification system being employed. Within the classification of red soil, several sub-orders such as, but not limited to, Aquults , Humults, Udults, Ustults, Xerults and the like are known by those skilled in the art. All these types of red soil are useful in the composition, and contemplated to be within the scope of the invention. In some instance, the red soil is silt, while in other instances, the red soil is clay, and in further instances, the red soil is a combination thereof.
[0019] Cement is a commonly used binder in the construction industry. Several varieties of cement are known in the art, and include, for example, but not limited to, Portland cement; Portland cement blends that include Portland blast furnace, Portland flyash cement, Portland pozzolan cement, Portland silica fume cement, Masonry cements, Expansive cements, White blended cements, and the like; Non-Portland hydraulic cements such as but not limited to, Pozzolan-lime cements, Slag-lime cements, Supersulfated cements, Calcium aluminate cements, Calcium sulfoaluminate cements, Geopolymer cements made from mixtures of water-soluble alkali metal silicates and aluminosilicate mineral powders such as fly ash and metakaolin; and the like. Combinations thereof may also be used herein. Other variations such as coloured cements, finely ground cements and so on may also be used in the composition of the invention.
[0020] The composition also comprises lime, which is a general term for calcium-containing inorganic materials, in which carbonates, oxides and hydroxides predominate. Lime is typically mined from rocks and minerals, typically limestone or chalk, that largely comprise calcium carbonate by cutting, crushing, pulverizing, chemically altering the source, or through appropriate means. Other processes for converting lime, such as calcinations or slaking of lime, is known to one of ordinary skill in the art, and the resulting materials are also contemplated to be used in the composition of the invention. Lime is used in large quantities as building and engineering materials (in the form of, among other things, limestone products, concrete and mortar).
[0021] The composition may further comprise sand. As used herein, sand is finely divided rocks and minerals that have a particle size ranging from about 60 micrometers to about 2 millimeters that is chemically predominantly silica, especially in the form of quartz.
[0022] The composition is advantageously made by dry mixing the individual components to obtain a smooth uniform mixture in a free flowing manner. The mixing may also be achieved using known equipment, such as, but not limited to, tilting, non-tilting and reversing, and transit mixers.
[0023] The composition may further comprise water, and/or other fluids to enable smooth mixing of the components. Following the mixing, the fluid if present may be evaporated or separated from the composition through known means to provide the composition of the invention. Alternately, a certain amount of the fluid, such as water may be left behind in the composition to facilitate further processing. The exact amount of the fluid to be left behind in the composition depends on various factors, such as, but not limited to, the next processing steps, nature of the fluid, and so on. These can be arrived at without undue experimentation by one skilled in the art.
[0024] The invention also provides a method for making compressed stabilized earth blocks using the novel composition that involves Terrazyme as mentioned herein. The method comprises a step for mixing red soil, Terrazyme, cement and lime in appropriate quantity to provide the composition of the invention. The method then includes a step for mixing composition of the invention with water to provide a wet composition for compressed stabilized earth blocks. The exact amount of water needed to make the wet composition may be easily arrived without undue experimentation by one skilled in the art. In one particular instance, the amount of water required for making the wet composition ranges from about 10 weight percent to about 20 weight percent relative to the total weight of the composition of the invention.
[0025] The method then involves a step for moulding the wet composition for compressed stabilized earth blocks to provide the compressed stabilized earth blocks. Moulds for making the compressed stabilized earth blocks are known in the art, and may be suitably used to make the compressed stabilized earth blocks of the invention. The conditions for moulding depend on the wet composition for compressed stabilized earth blocks, the nature of the final compressed stabilized earth blocks required, and so on, and may be arrived at without undue experimentation by one skilled in the art.
[0026] In yet another aspect, as noted herein, the invention provides a compressed stabilized earth block made by the method of the invention using the composition of the invention as described herein. The CSEB also provide a low cost green building block, which further addresses the problem of disposal of granite dust that has been a serious environmental hazard.
EXAMPLE
[0027] Red earth with appropriate clay and sand content was selected for the preparation of CSEBs. The soil was characterized for its physical properties as per Bureau of Indian Standards (BIS). This was conditioned and stored in bins before being used for making CSEBs.
[0028] The Ordinary Portland Cement tested for fineness, normal consistency, initial setting time and specific surface area as per Indian Standards was used in this investigation. In order to prepare the CSEBs using a hand operated soil block making machine, freshly prepared, characterized and conditioned quick lime (as stabilizer) was used as lime stone. Optimum dosage of Terrazyme for the soil was arrived by testing the soil with different dosages. Various proportions of sand, silt (size), clay (size) and admixtures used for various soils and different proportions with and without Terrazyme have been used in this investigation. The dimensions of the mould used to prepare the soil blocks were 230 mm x110 mm x75 mm. Some of the important parameters to be considered to get good quality blocks include initially mixing of proper quantities of the ingredients (sand, soil, optimum dosage of terrazyme and the admixtures of lime and cement) in a suitable condition and optimum water content. The workable range of Terrazyme content was found to be between 0.0025 - 0.075ml/kg for the preparation of the blocks. Some test compositions are listed in Table 1.

Table 1: Proportions of various ingredients used in the preparation of CSEBs
[0029] The wet compressive strength of a test CSEB block obtained by utilizing Terrazyme has yielded around 3.73 MPa and water absorption as low as 10 % for 2 months of ageing, which can be rated as a very good quality bricks suitable for any load bearing masonry units. For CSEBs after 1 months of ageing, durability studies in the form of 12 cycles of alternate wetting and drying have indicated 0.41 % loss of mass, relatively very high wet compressive strength of nearly 6.7 MPa and water absorption of less than 9 %. Further, with ageing the CSEBs are expected to gain more strength and may be expected to yield higher values of strength.
[0030] The CSEBs were prepared by using a hand operated soil block making machine known asMardini press , The dimension of the mould used to prepare the soil blocks was 230 mm x110 mm x 75mm. The required quantities (weight basis) of the ingredients namely sand, , soil and the admixtures lime and cement as obtained from the calculations depending on the proportion series were weighed and mixed dry initially. Then the optimum water content needed to mould the bricks and eject them successively as one unit was determined by mixing the dry mix of the ingredients with minimum water to obtain a good intact ball of the mix without sticking to the hand. By conducting few trials, this optimum water content was observed to be around 16 % on weight basis of the mix. For making soil blocks, the proportioned dry mix was spread on big tray and the requisite water was sprinkled to the mix and thoroughly worked with hand to have uniform distribution of moisture. Care was taken to use hand gloves while remoulding the mix. Then the wet mix was transferred to the mould placed in position on theMardini Press. The wet mix was remoulded in the mould using a wooden mallet to give proper hand compaction. The stiffened lid of the mould was closed. Using the toggle lever mechanism provided in the machine, the mix was compacted. Then the soil block was ejected, weighed and serially labeled with date of manufacture, date of testing and a suitable identification number (for the series adopted) for ease of future identification.
[0031] The CSEBs blocks with the novel approach of utilizing Terrazyme composition provide an extremely useful alternative low cost stabilizer for the construction industry resulting in reducing the quantity of traditional stabilizers and dependency of cement in manufacture of bricks and also provide a low cost green building block.
[0032] While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

COMPOSITIONS COMPRISING TERRAZYME FOR COMPRESSED STABILIZED EARTH BLOCKS (CSEBs), METHODS THEREFOR, AND CSEBs THEREFROM
ABSTRACT
[0033] In one aspect, the invention provides a composition for making compressed stabilized earth blocks. The composition of the invention comprises red soil; Terrazyme; cement; and lime. In another aspect, the invention provides a method for making compressed stabilized earth blocks. The method comprises mixing red soil, Terrazyme, cement and lime to provide the composition of the invention. The method then includes mixing composition of the invention with water to provide a wet composition for compressed stabilized earth blocks. The method then involves moulding the wet composition for compressed stabilized earth blocks to provide the compressed stabilized earth blocks. In yet another aspect, the invention provides the compressed stabilized earth blocks using the novel composition.

We Claim:
1. A composition for making compressed stabilized earth blocks, wherein the composition comprises:
red soil;
Terrazyme;
cement; and
lime.
2. The composition of claim 1 further comprising sand.
3. The composition of claim 1 wherein the Terrazyme is present in a concentration ranging from about 0.025 ml to 0.075ml, cement is present in a range of about weight percentage of 2% to 6% and lime is present in a range of about 0-4% relative to a total weight of the composition for compressed stabilized earth blocks.
4. The composition of claim 1 wherein the red soil is at least one of silt, clay or combinations thereof.
5. A method for making compressed stabilized earth blocks, wherein the method comprises:
mixing red soil, , cement, and lime to provide a composition for compressed stabilized earth blocks;
mixing the composition for compressed stabilized earth blocks with water to provide a wet composition for compressed stabilized earth blocks; and
moulding the wet composition for compressed stabilized earth blocks to provide the compressed stabilized earth blocks.
6. The method of claim 5 wherein the composition for compressed stabilized earth blocks further comprises sand.
7. The method of claim 5 wherein the red soil is at least one of silt, clay or combinations thereof.
8. A compressed stabilized earth block having a composition comprising red soil; Terrazyme; cement; and lime.

Signature of Authorized Representative

Rachna Singh Puri
IN PA 348

Date: